I don't know the answer. But I think it might to do with the condition of the bulbs/clove before planting. Were they kept in cold, or room temperature ?, how fresh/old were they ... ?

If you planted the Russian Inferno correctly (and I assume you did) then they should be fine. It's not neccesary for garlic to sprout before winter, all it needs to do is grow roots. Now if they don't show up next spring, then you've got a problem.

If you're curious you can carefully dig up a clove and check for signs of growth.

Rodney

The Cloves were kept in a brown paper bag at room temperature. I had received the cloves 2 weeks prior to planting them.

Thanks for the replies... all of my other garlic has sprouted (except a few of the spanish roja)... so I'll wait it out and see.

Some Russian varieties (don't know about that one) were valued for Storage qualities. That would also mean slower sprouting.

Garlics naturally have tendency to sprout in cooler temperature. I heard this some years ago NOT to store your gralics in the frig as it will hasten sprouting. Instead, keep it at 50 to 65F or at room temper.
So it is possible for a variety to require some colder soil temperature to sprout . And also, I think that garlic has a time clock. That means, it will not sprout any/every time that you plant it; it has a mind of its own.

Sorry about late post. By now your Russian inferno probably came up. I grow Russian inferno and always seems to be the last to emerge, do not know why. Russian inferno is an asiatic garlic which as a group emerge later than other varieties. Hope that helps, but I suspect by now you have seen some sprouting.